New Zealand’s Transport Accident Investigation Commission (TAIC) has added mast bumping accidents involving Robinson helicopters to its Watchlist of pressing safety concerns. There are approximately 300 Robinson helicopters registered in New Zealand, comprising about 40 percent of the country’s total helicopter fleet, the TAIC said in announcing the Watchlist addition.
Mast bumping is contact between an inner part of a main rotor blade or rotor hub and the main rotor drive shaft or mast, TAIC said in its Watchlist documentation. “Mast bumping usually results in the helicopter breaking up in flight, which is fatal for those on board. Since 1996, TAIC or the New Zealand Civil Aviation Authority have investigated 14 mast bumping accidents involving Robinson helicopters. Eighteen people died in those accidents, TAIC said.
“We understand what mast bumping is, but it is often difficult to determine exactly what happened to cause the mast bump,” said TAIC Commissioner Stephen Davies Howard.
TAIC also said that the rate of Robinson in-flight breakup accidents in New Zealand had not been significantly reduced by the adoption of U.S. Federal Aviation Administration measures intended to help prevent such accidents.